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1. Problems for Pencil and Paper The foundation of mathematics ...

1. Problems for Pencil and Paper The foundation of mathematics ...

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We emphasize that the ability to do arithmetic with fractions by h<strong>and</strong> is important. It isnecessary <strong>for</strong> success in algebra; a skill with decimals but not fractions (<strong>for</strong> example, being ableto h<strong>and</strong>le operations with fractions solely by means <strong>of</strong> a calculator) is not adequate. Indeed,fluency in the arithmetic <strong>of</strong> fractions is crucial background <strong>for</strong> developing fluency in the algebra<strong>of</strong> fractions. For fractions appear in algebra in the <strong>for</strong>m <strong>of</strong> algebraic expressions that cannotbe treated as numbers on a calculator. Besides this, fractions play a key role in underst<strong>and</strong>ingstatistics <strong>and</strong> probability (<strong>and</strong> conversion <strong>of</strong> fractions to decimals makes its almost impossibleto trace an error or to easily assess how the answer will change if a problem is changed slightly).In the following problems we illustrate these skills.algebra <strong>and</strong> basic trigonometry <strong>of</strong> a similar flavor.We also include several problems in1:234 + 582 = 901 − 74 =582 × 7 = 392 ÷ 7 =Discussion: Prior to doing these calculations, students must be able to add <strong>and</strong> multiply onedigit numbers automatically (that is, without pencil <strong>and</strong> paper, <strong>and</strong> quickly, without the needto compute) with complete accuracy. <strong>The</strong>y should also be able to do the inverse problems(subtraction, division, such as 16 − 9, 56 ÷ 8) automatically. <strong>The</strong> ability to do these basiccalculations automatically is fundamental <strong>for</strong> all that follows.2:357+ 842+ 2, 3923: Calculate 37 × 79. <strong>The</strong>n calculate 37 × .79.4: Calculate23| 805 <strong>and</strong> also 2.3| 8.055: Convert each <strong>of</strong> the following to a whole number, a proper fraction in lowest terms or amixed number with fractional part in lowest terms.2

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